In some of the multimedia framework, we send the spec info such as VC1 Profile Type (AP/SP/MP) and bit stream format (RCV) as the first frame between WMV parser and WMV decoder. The spec info is for initializing WMV decoder.
I am using the default Media Foundation WMV Source and my own WMV decoder MFT. When I dump the data from the MFT, it only has the video data and no spec info. So, I think that the spec info is set using some other interface.
Can someone give me a litter message about this?
By spec info if you mean VC1 sequence header then look at MF_MT_USER_DATA attribute. When MF Session Manager calls SetOutputType() of your decoder MFT, it supplies MF_MT_USER_DATA as a blob. Following snippet might give you a hint.
HRESULT SetOutputType(DWORD dwStreamID, IMFMediaType* pmt, DWORD dwFlags)
{
...
BYTE* seqData;
DWORD seqLength;
HRESULT hr;
hr = pmt->GetBlobSize(MF_MT_USER_DATA, &seqLength);
if (SUCCEEDED(hr))
{
seqData = (BYTE*) malloc(seqLength);
if (seqData != NULL)
{
hr = pmt->GetBlob(MF_MT_USER_DATA, seqLength, &seqLength);
}
}
/* Use MF_MT_USER_DATA to do something. */
...
}